Check chest chest and any shulkerboxes within chest for item with specific custom_model_data

I've managed to check if there's an item in a chest with the custom model data but I want to be able to check any shulker boxes in the chest as well, is this possible with predicates without making it super long by having to write one for every slot?
Why does the "container" work differently for shulkerbox in the chest vs the chest itself?